The invention relates in general to a paper transportation trolley.
Printing machines are loaded with printing material by a paper feeder, and the printed material is removed from the printing machine by a delivery device. Because of a substantial amount of printing material, special paper transportation trolleys are used for transporting the printing material. Such paper transportation trolleys are mobile, and they supply the printing material to the printing machine or deliver it from the printing machine. The paper transportation trolley is brought to the printing machine, and the printing material is received on a pallet of the printing machine or removed therefrom. There is a danger that the printing material may not be placed or stay registered and straight on the pallet.
It is an object of the invention to provide a paper transportation trolley which can reliably transport printing material and put it on, or remove it from a printing machine.
To facilitate undocking or release of a retainer device and the paper transportation trolley from the printing machine, a coupling device is provided with a release mechanism. For monitoring accurate coupling of the paper transportation trolley with the coupling device, a switch is provided in the retainer device, the first switching position of the switch corresponding to the released position of the paper transportation trolley and the second switching position of the switch corresponding to the locked position of the paper transportation trolley. In a preferred embodiment of the invention, conical locator pins are provided on the paper transportation trolley frame for engaging with the paper lift table for aligning pallet transfer between the paper transportation trolley and the paper lift table. These features allow for reliable transfer of the pallets on which the printing material is located from the paper transportation trolley to the paper lift table and vice versa. The paper transportation trolley is coupled to the coupling device with substantially low effort by means of guide rollers on first guide members of the paper transportation trolley for guiding second guide members of the coupling device over the first guide member. In a preferred manner, the printing machine has the second guide members, the retainer device, and a first stop, which are movable, and the paper transportation trolley has the first guide members, the guide rollers, and a second stop, as well as a lock pin for engaging the retainer device, which are movable.
It is preferred that the paper transportation trolley according to the invention and the respective devices of the printing machine be fitted to each other, and, more specifically, it is preferred that they be standardized in such a manner that the paper transportation trolley be compatible and interchangeable with different printing machines. The mating elements can be made individually adjustable.
The invention, and its objects and advantages, will become more apparent in the detailed description of the preferred embodiment presented below.